1.The purpose of using VFD:Contsant pressure or Constant torque etc.

2.The load type of VFD:Such as vane pump or volume pump etc,Please pay special attention to the performance curve of the load, the performance curve determines the way and method of application.  

3.It hs to be matched  between VFD and load:

3.1) Voltage to be matched:The rated voltage of the VFD should match the rated voltage of the load。

3.2) Current to be matched:For normal centrifugal pumps, the rated current of the VFD matches the rated current of the motor. For special loads ,such as deep well water pumps, it is necessary to refer to the motor performance parameters to determine the VFD current and overload capacity with the maximum current.

3.3)Torque matching to be matched:This application is used for under constant torque load or when there is a deceleration device.

  4. When using a VFD to drive a high-speed motor, due to the low reactance of the high-speed motor, the increase in high harmonics leads to an increase in the output current value. Therefore, the capacity of the VFD used in high-speed motors is slightly larger than that of normal motors. 

  5.If the VFD needs to run with a long cable, measures should be taken to suppress the impact of the long cable on the ground coupling capacitance to avoid insufficient output of the VFD. Therefore, in this case, the VFD capacity should be enlarged by one level or at the output end of the VFD and Install the output reactor.

  6. For some special applications, such as high temperature and high altitude, the VFD capacitance will be decreased , and the VFD capacity should be enlarged by one level.